[RFI] Observations of a low RFI Plasma TV and a very bad RFI plasma - same QTH

[WD8ARZ]

Appreciate all of those that made contributions to this email below.

Over the years, like most of you, I have had a variety of products in my 
home, from entertainment, washers, driers to ham radios etc.
What was  good brand for me on one purchase, may not have been so a few 
years later.

However a common problem in various modern devices can be the power 
supply. The old transformer designed power supplies didn't appear to be 
a problem very often. However the modern switching supplies can be real 
RF generators. That is aggravated by those switching supplies not having 
a true On / Off switch that total removes power from the switching power 
supply ... even though the device appears off, the switching power 
supply is not.

As mentioned below, when there are radiators that act as antennas, that 
RF noise can be severe.

Sometimes turning off the device will reduce the noise from switching 
power supplies, but I doubt it is totally gone due to the house wiring 
spreading the noise around. Unplugging the device will eliminate the rfi 
and protect the power supply from power line transients that switching 
supplies can be damaged by (that was rare on transformer power supplies 
when they were turned off at the set).

So when your looking for a problem RFI source, don't just rely on the on 
/ off switch of the device.... unplug it instead for doing your comparison.

Regards and 73 from Bill - WD8ARZ

On 9/11/2012 2:52 PM, Kirby Hallenbeck wrote:
> Since so much has been posted about how Plasma TV's are bad RFI generators,
> the following post may be interesting to those who prefer the picture
> quality of plasma and require low RFI.  Jim K9YC requested I repost it here,
> from the Elecraft reflector.  Jim's comments are followed by the original
> post. I will also note that another owner of the same set wrote me off list
> to say he had the same low RFI experience. So perhaps the all plasmas are
> bad is not true, and really comes down to how the sets are engineered. I
> will also note I took apart the Samsung ( to harvest boards for resale)  Jim
> refers to below and found there is a lot of long between board interconnect,
> that could radiate, so Jim's theory has much merit IMO. I did have overkill
> chokes and turns on every cable in and out of the bad TV  BTW.
>
>   
>
> On 9/10/2012 8:12 PM, Kirby Hallenbeck wrote:
>
>> I will also note that both sets were treated with the large ferrite cores
>> K9YC did the group buy on a while back and I haven't done a before after
>> cores on the Panasonic, as I just put them on when I installed it.  I did
> do
>
>> a before after on the Samsung and although it helped the Samsung was so
> bad
>
>> that I couldn't totally suppress it.
>   
>
> Kirby -- PLEASE post your excellent and detailed observations on the RFI
>
> reflector.
>
>   
>
> One observation about the result of your application of chokes. I'm
>
> thinking particularly of the Samsung box, but the concept applies to ALL
>
> equipment.  Chokes on cables leaving a noise source, or entering a
>
> victim, kill the part of the RFI that is conducted out of the set on
>
> those cables and RADIATED by those cables acting as antennas. Chokes
>
> cannot do anything about the trash that is radiated by WIRING INSIDE THE
>
> BOX. So -- the trash you heard after you applied the chokes, assuming
>
> that the chokes were ENOUGH to kill current those external wires, the
>
> remaining trash was from inside the box, and you'll never kill it
>
> without a major science project inside the box.
>
>   
>
> Original post on Elecraft Relflector
>
>   
>
> Message: 7
>
> Date: Mon, 10 Sep 2012 20:12:47 -0700
>
> From: "Kirby Hallenbeck" <1sailorman at comcast.net>
>
> Subject: [Elecraft] K3 3 & Plasma - Panasonic owner experience
>
> To: <elecraft at mailman.qth.net>
>
> Message-ID: <011b01cd8fcb$524e7920$f6eb6b60$@net>
>
> Content-Type: text/plain;     charset="us-ascii"
>
>   
>
> I have the predecessor of the Panasonic you are looking at, a TC-P65VT30,
>
> which was manufactured August 2011. I can tell you that mine is surprisingly
>
> quiet. I had a Samsung 58b860y2fxza prior to this that was unbelievably
>
> obnoxious, to the point I had to turn it off to communicate on my morning
>
> 75m net and it splattered other bands too. I could actually here the noise
>
> pattern change in response to changes in the raster on the TV.
>
>   
>
> I was lucky, in an RF sense, my disabled son cracked the screen on the
>
> Samsung, forcing me to re-evaluate brands. Since I put way through college
>
> fixing TV's among other things, I have pretty extensive contacts with people
>
> still in that business, and they all gave the nod to Panasonic, when it
>
> comes to Plasma, from reliability, to picture, to support from the manuf.
>
> After seeing both companies, I tend to agree. I wrote Samsung about the
>
> issue requesting they address the issue and they didn't even respond. The
>
> servicers don't like Samsung either, so steer clear of them. You will
>
> absolutely love the Panny set. As a past servicer with very picky eyes that
>
> like the CRT look, you will not have any regrets, unless you are looking for
>
> super bright LCD fluorescent display, which to me is not the (natural) look
>
> I like.
>
>   
>
> I will also note that both sets were treated with the large ferrite cores
>
> K9YC did the group buy on a while back and I haven't done a before after
>
> cores on the Panasonic, as I just put them on when I installed it.  I did do
>
> a before after on the Samsung and although it helped the Samsung was so bad
>
> that I couldn't totally suppress it.
>
>   
>
> For those not familiar with the Model numbers, the sets we are talking about
>
> are/were the flagship models, so mileage may vary on lower end models.
>
>   
>
> Kirby - AF6OP
>
>   
>
>> Subject: Re: [Elecraft] K3 & Plasma Question
>>> We are now in the market for another TV, and have been looking at a very
> nice Panasonic 65" Plasma set, model TC-P65VT50. I've already told the Best
>
> Buy sales manager that IF we do buy it and IF it causes QRN to the HF bands,
>
> it is coming right back. He said that is no problem. But, if I can query
>
> this group to see if anyone else has one of these TV's, I may be able to
>
> avert a lot of work ahead of time. Our second choice would be an LED set,
>
> but after seeing plasma and LED side by side, playing the exact same
>
> content, I want to stay with plasma - BUT ONLY IF IT DOESN"T SCREW UP THE
>
> K3!!!
>
>   
>
> _______________________________________________
> RFI mailing list
> RFI at contesting.com
> http://lists.contesting.com/mailman/listinfo/rfi
>